Correlation of Flicker Induced and Flow Mediated Vasodilatation in Patients With Endothelial Dysfunction and Healthy Volunteers.

July 1, 2008 updated by: Medical University of Vienna

Correlation of Flicker Induced and Flow Mediated Vasodilatation in Patients With Endothelial Dysfunction and Healthy Volunteers

A couple of studies have shown that illuminating the eye with diffuse flickering light is accompanied by an increase of retinal vessel diameters, optic nerve head blood flow and retinal blood flow. We have recently used this visual stimulation technique as a new and powerful tool for the non-invasive investigation of vascular reactivity. Additionally, we could show that this response is diminished in patients with vascular pathologies and that the response is dependent on nitric oxide, indicating that flicker induced vasodilatation may reflect endothelial dysfunction and may be a new approach to test endothelial function in vivo.

One of the most widely used method for the assessment of endothelial function is flow mediated dilatation (FMD). FMD has been shown to give a reliable estimate of vascular function in vivo. In the present study, we set out to compare the standard method for the evaluation of endothelial function, FMD, to flicker induced vasodilatation in the retina.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

80

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Austria
      • Vienna, Austria, 1090
        • Department of Clinical Pharmacology, Medical University of Vienna

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

Patients with diabetic retinopathy:

  • Men and women aged > 18 years.
  • Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant.
  • Inclusion criteria of patients are insulin dependent diabetes mellitus (IDDM) with non or mild non-proliferative diabetic retinopathy. Patients with no signs of diabetic retinopathy (level 1) or patients with one or more microaneurysms (level 2) will be included. Level of diabetic retinopathy will be assessed according to the criteria defined in the AREDS-study.(1991)
  • serum cholesterol < 250 mg/dl (treated or untreated)

Patients with mild hypertension and/or hypercholesterinemia:

  • Men and women aged > 18 years.
  • mild essential hypertension defined as a blood pressure meeting the criterion of hypertension grade 1 of the World Health Organisation blood pressure classification
  • systolic blood pressure between 140 and 159 mmHg and diastolic blood pressure between 90 and 99 mmHg and/or
  • serum cholesterol > 250 mg/dl
  • blood pressure will be measured at two different occasion in a sitting positions

Healthy subjects:

  • Men and women aged > 18 years.
  • Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant
  • normal ocular findings
  • serum cholesterol < 200 mg/dl
  • systolic blood pressure between 110mmHg and 140mmHg
  • diastolic blood pressure < 90 mmHg

Exclusion Criteria:

  • Abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
  • Symptoms of a clinically relevant illness in the 3 weeks before the first study day
  • Blood donation during the previous 3 weeks
  • other ocular pathologies than diabetic retinopathy level 1 or 2
  • History or family history of epilepsy
  • Ametropy greater or equal than 3 dpt
  • systolic blood pressure < 100mmHg
  • diastolic blood pressure < 75mmHg
  • pregnant or lactating women

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: 1
IDDM
Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD)
Forearm blood flow measurement: baseline 1 min, 3 min after inflation of cuff, 4 min after 0.8mg Nitroglycerin
Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light
Stimulation with Flicker-light: 1 min, measurement without flickering light 4 min after 0.8 mg Nitroglycerin
Other: 2
Hypercholesterolemia and/or Hypertension
Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD)
Forearm blood flow measurement: baseline 1 min, 3 min after inflation of cuff, 4 min after 0.8mg Nitroglycerin
Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light
Stimulation with Flicker-light: 1 min, measurement without flickering light 4 min after 0.8 mg Nitroglycerin
Other: 3
age/sex matched healthy control subjects
Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD)
Forearm blood flow measurement: baseline 1 min, 3 min after inflation of cuff, 4 min after 0.8mg Nitroglycerin
Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light
Stimulation with Flicker-light: 1 min, measurement without flickering light 4 min after 0.8 mg Nitroglycerin

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Retinal vessel diameters (Retinal vessel analyzer)
Time Frame: 8 min
8 min
Forearm Blood Flow
Time Frame: 8 min
8 min

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Vienna

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

December 1, 2006

Primary Completion (Actual)

December 1, 2007

Study Completion (Actual)

January 1, 2008

Study Registration Dates

First Submitted

February 5, 2007

First Submitted That Met QC Criteria

February 5, 2007

First Posted (Estimate)

February 6, 2007

Study Record Updates

Last Update Posted (Estimate)

July 4, 2008

Last Update Submitted That Met QC Criteria

July 1, 2008

Last Verified

June 1, 2008

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • OPHT-180506

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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